Spray gun



March 4, 1947. A. F. JENKINS .2,416,923

' SPRAY GUN l Filed Aug. so, 194,3 2 sheets-sheet 1 March 4, 1947. A FJENKlNs 2,416,923

' SPRAY GUN` A l Fi leld Aug. 30, 1943 2 Sheets-Sheet 2 /jz 7. @la

o /l K@ V 3mm www@ we@ Patented Mar. 4, 1947 SPRAY GUN Alexander F.Jenkins, Baltimore, Md., assignor to The Alexander Milburn Company,Baltimore,

Md., a corporation ofi'Maryland Application August 30, 1943, Serial No.500,579

7 Claims.

In a spray gun of the type now generally employed for applying paint,enamel or other liquid coating material to surfaces for the purposes ofprotection, ornamentation, or the like, the liquid material is aspiratedthrough a valve controlled orice disposed centrally of the forward faceof the nozzle of the gun, by means of an .annular jet of air underpressure; and if a relatively flat or fan-shaped spray is required,convergent supplemental jets of compressed air are. directed throughlaterally disposed orifices in the nozzle so as to impinge upon thecentral jet of aspirated liquid and convert this substantiallycylindrical or conical jet into one having an oval or even anapproximately rectangular cross sectional configuration.

Heretofore, or rather until the conception of my invention covered by U.S. Patent No. 2,126,888, granted me August 16, 1938, the spray modifyingjets have been in the form of solid cones emitted from ne circularorifices formed very accurately in the side portion of the nozzle sothat the jets Will impinge exactly upon opposite sides of the axis oftheI liquid jet. The liquid coating material is frequently also suppliedto the. gun under some degree of pressure and valves for regulating thepressures and quantities of the liquid and of both the aspirating andspray modifying air supplies are generally provided on the guns. Thedegree of atomizationrequired,v the nature and viscosity -of the liquidto be sprayed, and the desired shape of the sprayal1 of these factorsdetermine the degree of adjustment necessary for these regulatingdevices; and in most cases the relative pressures are quite critical andmust be very accurately controlled.

In the use of spray guns of the usual type in which solid supplementaljets of spray modifying air are employed, there is a tendency to cause asplit in the spray, that is, a narrowing' of the cross section of thecenter of the spray and a lessening of the densityof the spray at thispoint and an increase in density at the end portions thereof due to theunequal atomization of the sprayed liquid. To correct this condition,the usual practice, in constructions which permit it, is to reduce thesupply of air to the supplemental jets. This adjustment, however,reduces the width of the spray and is apt to alter the 'fcharacter ofthe spray in otherl ways, especially when made in connection with theuse of highly viscous and difficulty atomizable materials such assynthetic enamels and the like.

In the specification accompanying my Paten No. 2,126,888, I havedescribed a spray gun in which tubular or hollow conical spray modifyingjets of vair are provided, either alone or in conjunction with solidjets. By this means, a better atomization and distribution of the liquidmaterial may be attained and the splitting eliminated, while at the sametime there may be employed higher pressures or greater volumes ofmodifying air.

The present invention provides a modification of the nozzle disclosed inmy. aforesaid patent, by means of which an even better atomization anddistribution of the sprayed material may be attained.

The invention in its preferred embodiment contemplates the provision ofay substantially oval or elliptical annular opening or orifice for thespray modifying or fanning jets upon the wings of the nozzle. The longaxes of the elliptical orices preferably extend transversely of thenozzle and the short axes are in alignment, and if extended intersectthe axis of the main jet of the nozzle at the same point.

I have found that the provision of an oval or transversely widened oriceproduces a wide final spray of extraordinary uniformity, eliminating allspottiness or heaviifiess in the outer edges of the spray pattern. Theuse of a substantially oval spray modifying jet also renders both theair and coating fluid pressure regulation much less critical andactually reduces by a considerable amount the pressures required toproduce an even pattern of adequate coverage.

`The objects of the inventionalso include novel methods and apparatusfor providing and adjusting the orifice through which the oval annularspray modifying jet is emitted.

Other objects of the invention and features of novelty will be apparentfrom the following specification when read in connection with theaccompanying drawings in which one embodiment of the invention isillustrated by way of the Figure 4 is an end View of a pin or plugemployed to form the annular jet orifice; v,

Figure 5 is a View in side elevation of the plug; Y Figure 6 is afragmentary View of the inner or forward Vface of one Vof the side wingsof the nozzleshowing one form of annular oval orifice;

Figures '7, 8, 9, and 10 are similar views showing modifications inwhich the widths of the orice are varied at either the sides or endsthereof by either widening the opening in the nozzle or by narrowing thecorrespondingdimensions of the inserted pin; Y I

Figure 11 is a similar view showing the substantially oval orillceflattened on four sides Vto the shape of a lozenge;

,4 y ber32 formed between Vthe conical tip 25 of the liquid nozzle andthe walls of the central air cap 35.

ThisV air cap 35V isprovided with the annular rearwardly extendingflange v36 which lits around the annular flanged@ which extendsforwardly from the portion 22 ,of the liquid nozzle; flange 35 extendsrearwardly7 to fabut theY intermediate flange 22 of the liquid nozzlerand is pros Y vided with a radially outwardly directed flange I 30which is spaced from the ange 22 so as to leave an annular space l3|into which a screw-- y driver or vother suitable tool may be inserted inFigures 12 and 13 are views in side end elevation respectivelyl'of atool for placing or f centeringthe rinserts or pins in position'whilethey are being secured to the nozzles.v Figures 14 l5 yare similar viewsof a tool for adjusting the inserts in directions along the lon-g axisof the orifice; and l Figures 16 and 17 are similar views of Va tool yVfor making adjustments along the short exis.

Referring `more particularly to Figure l of 'the drawings the numeral I0designates the forward body portion of the spray gun whichmay be of anydesired constructionso far as the actuatingV and controlling mechanism`is concerned. VFor,

example it may follow, except as indicated otherwise herein, theVlconstruction. of the spray fgun illustrated in my Patent No,2,269,0577Qdated Jane,

I The body portion of the spray gun is provided with a liquid chamber orpassageway!! and a main air passageway ila. The air passageway is Yflange 44 of the clamping ring 45 may engage.

divided'adjacent the valve'seat i3V to provide 2 forwardly directedpassageway I4 leading to the 'supplemental flattening jetsof the air capand the diverging passageway l5 leading to the centralaspiratingrairoriflces.V A'reciprocating valve Y member ,I2 cooperateswithy the valve'seat 3 to ,,45

controlV the passage of air through the passage I4. The forward Vface l@-of the body-portion of the gun is ordinarily formed in a .singleplane,` although'within the scope of the invention the construction ofthe body vary widely. j Y

The inner liquid nozzle portion is indicated generallyl by the referencenumeral-1320 and com- ,portion of the gun may order to remove the'cap ortip S5 from the liquid nozzle.- The flange ISB also provides an abut-`ment element for the surrounding inner portion vof Ythe annular'auxiliary jet air cap d2. VPrefIn erably the inner wall 355 of theliquid nozzle 20 is shaped as shown in Figure 1 and terminatesshortv'ofY .the converging front walls of the cap 35 so as' to provideas much of anenlargement nozzle tip 25 at a predetermined distance'topro? vider the annular aspirating air orifice de.

The' outer annular air cap of this Vtype of nozzle assembly is indicatedgenerally by the reference numeral #i2 Yand is provided with vacen-ltral annular surface 3l which nts around the flange 35 of thesupplemental air tip 25.' The air cap is provided rearwardly `with anoutwardly extendingV anrnilarV flange 43 which forms a shoulder aboutwhichv the inwardly directed The clamping ring 45 is threaded to theouter kkperiphery of an intervening annular thread carrying element H0which isdisposed between the flange 22 of theV liquid Vnozzle and theforward face of the body of thegun. The'inner an- `nular surface HI oflthe insert Il@ fits around the central projecting portion H2 ofthegfront `end kof the `gun and is sealed against therearward 'steppedface IIS of the body portionY il) as by means of the gaskets H5'. i

An inwardly disposed ring or washer tral air supply passing through thepassageway E5 before it enters the passageways Se. The anprises thecentral rearwardly projecting nipple Y' which is threaded as at Y2linto'the recess IiiY formed in the forward portion I0 ofthe main' bodyof the gun. The centralportion of. the liquid nozzle20 is provided witha flange 22,1;he

nular intermediate member VI I Il is also'provided with the annular'recess or forward `annular chamber 20 which is placed Yin communicationwith the air supply passing through the passageway I rin the body ofthegunby means of the series of Vholesl I 2l. An inwardly projectingflanged baille ring |22 and an outwardly projectperiphery of Iwhich maybe squared for the appliv cation of a wrench or other suitable tool for.removing and-applying this portion of :the nozzle to the spray gun. Theforward end of the liquid nozzlel proper is` of la general conicalcongurav v tion asl indicatedrat 25 and is provided centrally at the tipthereof with a liquid orifice 26, the flow of liquid through thisrorice.being, controlled byv ing ring |23 are fitted withinfthe chamber -IZ inorder to equalize the distribution of the auxiliary jet air supply uponopposite 'sides' of the air means of the needle valve 2 which projectsrear-` r wardly and is operatively connected with the trigger of thelgunwhich is not shown. herein, butv maybe of any usual or conventionalconstruction or may bearranged as shown in my Patents Nos. 2,082,060 and2,082,061. The intermediate flange` 22 isv provided with an annularseries of passagen ways 30 which constitutea portionY of the comcap.

The,intermediate annular mem-ber H0 is provided around its outerperiphery .with 4the'screw threads I'25 upon which may be screwed ktheclamping ring d5 which is provided with, the flange or shoulder 44surrounding the shoulder 43oftheaircap. y r

At diarnetrically opposite points on the annu.- lar outer air cap 42vthere are provided the forwardly directed outwardly' divergentyprojections 50. These projections' areY of a substantially Vcircular orcylindrical"configuration and,v asbest shownin Figures ,1' andk 3, they'are provided with rearwardly disposedv substantially cylindrical'r'e- YThe sie isV held bythe flange iii of the' member VI-lllso as Y throughthese faces with the rear recesses or` The chambers 52 are placedinIchambers 52. communication with the bailled air chambers l20 in therearward portion of the nozzle of the gun by means of the parallelspaced ducts 54, the

rear ends of which open into the annular space,

i3d in the rear portion of the cap 42.

In order to close the rear end of the chamber 52 of the wings 5B of thenozzle cap, and also to shape the annular orifice in the forward facesof these wings there Aare provided the inserts or plugs 55. the outerheaded portion 5B, a circular shoulder part 5l which fits snugly intothe rear end of the recess or chamber 52, and the forwardly and innwardly projecting pin portion 58 which is of an oval or elliptical crosssection corresponding generally to the elliptical conguration'of theopening 53 in the wing projections 5U. The plugs 55 are inserted fromthe rear or outer side of the wings lill so that the parts 5l nt thechamber openings and the pins 53 are centered symmet rically with theopenings 53. This` centering must be very accurately done, and specialtools for accomplishing this purpose will be described. When properlyapplied and centered, the plugs are soldered firmly in place.

This arrangement results in the provision of a closed circular annularchamber into which the twin passageways 54 discharge air under pressure,and this air is then discharged through the oval or elliptical orices 8Dprovided in the faces of the wings. One of the resulting oval orifices55 is very clearly shown in Figure 6 of the drawings. It will be notedthat in the preferred embodiments the long axis of the ellipti calorifice is disposed transversely of the nozzle, while the short axislies in the same plane as the central axis of the spray gun. Thisarrangement has been found to provide an exceptionally satisfactoryspray modifying jet which produces a uniform wide pattern which does notvary sharply with changes in air or coating fluid pressure. However, forsome purposes it may be desired to arrange the long axis of theelliptical orifice in the plane of the axisof the gun instead of theshort one, and this variation also comes within the scope of the presentconception.A

In Figure 7, a modification of the uniformly wide annular spray jetorifice shown in Figure 6, is illustrated. In this arrangement the longdiameter De of the opening 53 of the nozzle is maintained atsubstantially the same dimension as shown-in Figure 6 but the longdiameter Dp of the pin 5ta is shortened, whereby there is providedoppositely disposed thickened portions 6|- at the ends of the orifice.This will afford somewhat more air at the ends of the spray pattern forcertain conditions of operation. In Figure 8 the same effect has beenattained by employing a pin 58 which is maintained at its originaldiameter shown in Figure 6, but the opening 53a has been lengthened asindicated al', D'o.

In Figure 9 of the drawings, the longer dimensions of both the pin 58hand the opening 53 have been maintained the same as in Figure 6, but thesmaller diameter of the pin 58h has been narrowed as at dp, thisproviding widened portions 52 upon each side of the orifice.

A similar effect is attained as shown in Figure 10 of the drawings bymaintaining the dimensions Each of these plugs is formed with' "of thepin 53 in both directions and by widening the opening 53D to thediameter do thus providing the widened portions on the longer sides ofthe orice.

In Figure l1 of the drawings, a substantially lozenge or rhombus shapedannular orifice 55 is provided by forming the nozzle opening 53e andVthe pin 58e with corresponding cross sections.

This configuration may be employed where it is not so important to havetheA spray pattern very wide at the ends.

In Figures 12 and 13 there is illustrated a tool l!! for use inpositioning or centering the elliptical pins 58 which cooperate withthel side jet openings 53. The tool l@ is formed with a convenientlyshaped shank 'il and a hollow or tubular portion '.12 of the exact shapeof the orifice Sil. After the plug 55 is inserted into the chamber 52and is roughly centered. by means of the shoulder portion 5l the end 'l2of the tool It is inserted from the forward or inner side of the winginto the orifice 55 thus accurately centering the pin 58 within theopening 53. Then the plug 55 is soldered firmly in place and finally thetool 'lll is withdrawn.

In the event that after application to the device a pin 58 is found notto be properly centered, or if it becomes displaced through use, it maybe recentered without dismantling the nozzle cap. In Figures lll and l5an adjusting tool l5 is shown which has an operating end l5 in the formof a half-oval, shaped to fit within one of the longer halve-s of anorifice 5i?. This tool is employed in'cases where the pin 5t approachesthe wall of Vthe opening 53 too closely at a point adjacent the endsofthe longer diameter. By inserting the end 16 of the tool l5 andcarefully exerting a gradual sidewise pressure, the pin 5S may bestrained toward its properly centered position. On the other hand, ifthe pin 58 is warped too closely to the wall of the opening 53 adjacentthe end of a short diameter, the tool Sii may be used, the end 3! beingshaped to occupy a long halfoval portion of the orifice 6i).

It is understood that the construction and arrangement of ther centralaspirating jet of the gun may be varied widely and still derive thesubstantial benefits and advantages of my novel oval modifying jets. Thecentral jets may correspond to those in my aforesaid patents or mayfollow the design of any known or anticipated aspirating jetarrangement.

Various changes and modifications may be made in the embodimentsillustrated and described herein without departing from the scope of theinvention as defined by the subjoined claims.

Having thus described the invention, what is claimed as new and desiredto' be secured by Letters Patent is:

1 In a spraying device of the class described, a nozzle comprising, incombination, means centrally thereof for discharging a liquid spray, andmeans disposed at each side of said first named means for discharging atubular jet of air against said spray to modify its cross sectionalconuration, said second named means each being so constructed andarranged that one diameter of said tubular jet is longer than thediameter at right angles thereto, the shorter diameters of the jetsbeing co-planar and directed so as to intersect the axis of the centralspray discharging means if projected.

'fa-natos Vvided axially thereof for discharging an atomized disposedmeans and directed so as to discharge holloW substantially tubular jetsof air of elliptical cross section'toimpinge upon opposite sides of saidspray at a point spaced from the face of the nozzle, in order to modifythecross sectional coniiguraticn of the spray, the shorter diameters ofthe elliptical orifices being co-planar and directed to intersect theaxis of the nozzle if projected.

3. In a spraying device of the class described, a nozzle comprising, incombination, means provided axially thereof for discharging an atomizedliquid spray, said nozzle also having an annular oriiice formed thereinupon each side of said axially disposed means and directed so as todischarge hollow substantially tubular jets of air to impinge uponopposite sides of said spray at a l point spaced from the face of thenozzle, in order to modify the cross sectional configuration of thespray, said annular orifices having one diameter longer than thediameter at right angles thereto, the shorter diameters being co-planarand directed to intersect the axis of the nozzle if projected. Y

4. In a spraying device of the class described, a nozzle comprising, incombination, means pro-v vided axially thereof for discharging anatomized liquid spray, said nozzle also having an annular orice formedtherein upon each side of said axially disposed means and directed so asto discharge hollow substantially tubular jets of'air to impinge uponopposite Vsides of said spray at a point spaced from the face of thenozzle, in order to modify the cross sectional configuration of the Yspray, said annular orices having one diameterv longer than the diameterat right angles thereto, the orifices being of lozenge shape,'theshorter` diameters being `co-planar and directed to interi sect the axisof the nozzle if projected.

5. In a spraying device of the class described, a

tion formed therein upon each side of said axially disposed means anddirected so as to discharge hollow substantially tubular jets of air ofelliptical, cross section to impinge upon opposite sides of said sprayat a point spaced from the face of the nozzle', in order to modify thecross sectional convfiguration of the spray, the shorter diameters, of Ythe elliptical orifices being co-planar and directed to intersect theaxis of the nozzle if projectedthe annular elliptical orice -being widerat theends of its longer diameter whereby the elliptical'tubular airjets are correspondingly thickened.

6. In a spraying device of the class described,

a nozzle comprising, in combination, means provided axially thereof fordischarging an atomized liquid spray, said nozzle also having an annularorice having a substantially elliptical cross section formed thereinupon each side of said axially disposed means and directed'so as todischarge hollow substantially tubular jets of air of elliptical crosssection to impinge upon opposite sides, of said spray at a point spacedfrom the face of the nozzle, in order to modify the cross sectionalconguration of the spray, the shorter diameters of the elliptical oricesbeing co-planar and directed to intersect the axis of the nozzle ifprojected the annular elliptical orice being wider at the ends of itsshorter diameter whereby the elliptical tu- Y bular air jets arecorrespondingly thickened.,

7. In a spraying device of the class described, a nozzle comprising, incombination, means provided axially thereof for discharging an atomizedliquid spray, said nozzle also having an annular orifice having asubstantially elliptical cross section formed therein upon each side ofsaid axially disposed means and directed so as to discharge hollowsubstantially tubular jets of air of elliptical cross section toirnpinge` upon opposite sides of said spray at a point spaced from theface of the nozzle, in order to modify the cross sectional con. gurationof the spray, the shorter diameters of the elliptical orifices beingco-planar and directed to intersect the. axis ofthe nozzle if projectedthe annular elliptical orifice being wider at the ends Vof one of itsprincipal diameters than at the ends of the other principal diameter.

ALEXANDER F. JENKINS.

REFERENCES CITED The following references Aare of record in the 45 le ofthis patent:

UNITED STATES VParrains Number Name Date Y Y v2,126,889 JenkinsY Aug.16, 1938 2,126,888 Jenkins Aug. 16, 1938 1,401,611 Landgrai Dec. 27,1921 1,948,818 Kettering Feb. 27, 1934 1,463,332 Parker et al. 'July 31,1923

